{{Short description|Species of algae}} {{Speciesbox | image = Ambystoma maculatum clear egg mass.JPG | image_alt = Ambystoma maculatum clear egg mass with green color from algae | image_caption = ''Ambystoma maculatum'' clear egg mass with green color from algae | range_map = | range_map_alt = | range_map_caption = | status = | status_system = | status_ref = | genus = Oophila | species = amblystomatis | authority = F.D.Lambert ex N.Wille<ref name=AB_s142847>{{AlgaeBase species|name=Oophila amblystomatis|id=142847|access-date=2026-01-18}}</ref> | synonyms = *''Chlorococcum amblystomatis'' <small>(F.D.Lambert ex N.Wille) N.Correia, J.Varela & Leonel Pereira</small> | synonyms_ref = <ref name=AB_s142847/> }} '''''Oophila amblystomatis''''' is a species of single-celled green algae known for its symbiotic relationship with the spotted salamander, ''Ambystoma maculatum''. It grows symbiotically inside salamander eggs, primarily in the eggs of the spotted salamander. It has also been reported in other salamander species, such as the Japanese black salamander, ''Hynobius nigrescens'', which is endemic to Japan.<ref>{{Cite journal |last1=Muto |first1=Kiyoaki |last2=Nishikawa |first2=Kanto |last3=Kamikawa |first3=Ryoma |last4=Miyashita |first4=Hideaki |date=2017-04-04 |title=Symbiotic green algae in eggs of Hynobius nigrescens, an amphibian endemic to Japan |url=https://onlinelibrary.wiley.com/doi/10.1111/pre.12173 |journal=Phycological Research |language=en |volume=65 |issue=2 |pages=171–174 |doi=10.1111/pre.12173 |bibcode=2017PhycR..65..171M |issn=1322-0829|url-access=subscription }}</ref> It is the only ''named'' species in genus '''''Oophila'''''.<ref name="AB_g51306">{{AlgaeBase genus|name=Oophila|id=51306|access-date=2022-02-23}}</ref>

== Taxonomy and etymology == ''Oophila'' ("egg-loving") is a reference to the algae's behavior of living with eggs.<ref name="AB_g51306"/> The specific epithet ''amblystomatis'' means "of ''Amblystoma''", an unaccepted spelling correction for the salamander genus ''Ambystoma''.<ref name=AB_s175845/> The species has alternatively been placed in genus ''Chlorococcum''.<ref name=AB_s175845>{{AlgaeBase species|name=Chlorococcum amblystomatis|id=175845|access-date=2022-02-23}}</ref>

Various isolates labelled as ''Oophila'' have a symbiotic relationship with amphibian (salamander and frog) eggs. Phylogenetic evidence indicates that such egg-loving green algae evolved not once, but twice, as so-called ''Oophila'' is actually polyphyletic and consists of two clades: one containing ''O. amblystomatis'' nested in ''Chlamydomonas'', the other mixed among ''Chlorococcum''.<ref>{{cite journal |last1=Vences |first1=Miguel |last2=Sachs |first2=Maria |last3=Irisarri |first3=Iker |last4=Bartels |first4=Fabian |last5=Eriksson |first5=Pontus F. |last6=Künzel |first6=Sven |last7=Kurabayashi |first7=Atsushi |last8=Laugen |first8=Ane T. |last9=Vegso |first9=Zachary T. |last10=Bishop |first10=Cory D. |last11=Kerney |first11=Ryan |last12=Arndt |first12=Hartmut |title=Phylotranscriptomic relationships of the Oophila clade of green algae associated to amphibian egg masses |journal=Molecular Phylogenetics and Evolution |date=November 2024 |volume=200 |article-number=108165 |doi=10.1016/j.ympev.2024.108165|doi-access=free |pmid=39117294 |bibcode=2024MolPE.20008165V }}</ref> In the Japanese black salamander ''Hynobius nigrescens'', two algae species, one from each clade, are present.<ref>{{cite bioRxiv | last1 = Genot| first1 = Baptiste| last2 = Abedin| first2 = Swapnil Eishraq| last3 = Shinozaki| first3 = Naoshi| last4 = Kerney| first4 = Ryan| last5 = Maruyama| first5 = Shinichiro| title = Two distinct green algal symbionts cohabiting in the Japanese black salamander Hynobius nigrescens| date = 2026-01-09| biorxiv=10.64898/2026.01.07.698294}}</ref>

== Growth == ''O. amblystomatis'' cells invade and grow inside salamander egg capsules. Once inside, it metabolizes the carbon dioxide produced by the embryo and provides it with oxygen and sugar as a result of photosynthesis. This is an example of endosymbiosis.<ref name="HSU">[http://www.hsu.edu/content.aspx?id=5910 Nature Trivia, Spotted Salamander] {{Webarchive|url=https://web.archive.org/web/20100802205227/http://www.hsu.edu/content.aspx?id=5910 |date=2010-08-02 }} at [http://www.hsu.edu/ Henderson State University]. Accessed 4 August 2008.</ref> The relationship between some salamanders and some species of green algae, including ''O. amblystomatis'', is the only known example of an intracellular endosymbiont in vertebrates.<ref name="Frazer2018">{{cite web|url=https://blogs.scientificamerican.com/artful-amoeba/algae-living-inside-salamanders-arent-happy-about-the-situation/|title=Algae Living inside Salamanders Aren't Happy about the Situation|last=Frazer|first=J.|date=2018-05-18|website=Scientific American|access-date=2018-05-21}}</ref><ref name="Burns2017">{{cite journal|last1=Burns|first1=J. A.|last2=Zhang|first2=H.|last3=Hill|first3=E.|last4=Kim|first4=E.|last5=Kerney|first5=R.|title=Transcriptome analysis illuminates the nature of the intracellular interaction in a vertebrate-algal symbiosis |journal=eLife|volume=6 |article-number=e22054 |year=2017|doi=10.7554/eLife.22054|pmc=5413350|pmid=28462779 |doi-access=free }}</ref> This symbiosis between ''O. amblystomatis'' and the salamander may exist beyond the oocyte and early embryonic stage. Chlorophyll autofluorescence observation and ribosomal DNA analysis suggest that this algal species has invaded embryonic salamander tissues and cells during development and may even be transmitted to the next generation.<ref>{{cite journal |last=Kerney |first=Ryan |display-authors=etal |year=2011 |title=Intracellular invasion of green algae in a salamander host |journal=PNAS |volume=108 |issue=16 |pages=6497–6502 |bibcode=2011PNAS..108.6497K |doi=10.1073/pnas.1018259108 |pmc=3080989 |pmid=21464324 |doi-access=free}}</ref>

Free-living ''O. amblystomatis'' have been reported growing in freshwater woodland ponds.<ref name=":0">{{cite journal |last1=Lin |first1=Yuan |author2=C. D. Bishop |date=2015 |title=Identification of free-living ''Oophila amblystomatis'' (Chlorophyceae) from Yellow Spotted Salamander and Wood Frog breeding habitat |journal=Phycologia |volume=54 |issue=2 |pages=183–191 |doi=10.2216/14-076.1 |bibcode=2015Phyco..54..183L |s2cid=83838616}}</ref> They grow best at a water depth of {{convert|30|cm|abbr=on}} with the water temperature being {{convert|15|C}} and an air temperature of {{convert|14|C}}. Their optimal pH tolerance ranges from 6.26 to 6.46. Cells are motile via a flagellum. ''O. amblystomatis'' can reproduce sexually and asexually. 16S rRNA has been partially sequenced as well as the 18S rRNA for the plasmid, however whole genome sequencing has not been done.<ref name=":0" />

==See also== * ''Chlorogonium''

==References== {{Reflist}}

==Further reading== {{Refbegin}} *{{cite journal|last=Gilbert|first=P. W.|year=1942|title=Observations on the eggs of ''Ambystoma maculatum'' with especial reference to the green algae found within the egg envelopes|journal=Ecology|volume=23|issue=2|pages=215–227|doi=10.2307/1931088|jstor=1931088 |bibcode=1942Ecol...23..215G }} *{{cite journal|last1=Kim|first1=E.|last2=Lin|first2=Y.|last3=Kerney|first3=R.|last4=Blumenberg|first4=L.|last5=Bishop|first5=C.|year=2014|title=Phylogenetic analysis of algal symbionts associated with four North American amphibian egg masses|journal=PLoS ONE|volume=9|issue=11|article-number=e108915 |doi=10.1371/journal.pone.0108915|pmc=4230919|pmid=25393119|bibcode=2014PLoSO...9j8915K|doi-access=free}} *{{cite journal|last1=Valls|first1=J. H.|last2=Mills|first2=N. E.|year=2007|title=Intermittent hypoxia in eggs of ''Ambystoma maculatum'': embryonic development and egg capsule conductance|journal=J. Exp. Biol.|volume=210|issue=14|pages=2430–2435|doi=10.1242/jeb.003541|pmid=17601946|doi-access=free |bibcode=2007JExpB.210.2430V }} {{Refend}}

==External links== * [https://web.archive.org/web/20100802205227/http://www.hsu.edu/content.aspx?id=5910 Green Eggs and Jam: Adaptations That Help Spotted Salamanders Reproduce] at [http://www.hsu.edu/ Henderson State University]. * [http://amphibiaweb.org/cgi-bin/amphib_query?query_src=&where-genus=Ambystoma&where-species=maculatum&rel-genus=equals&rel-species=equals ''Ambystoma maculatum''], the spotted salamander, at [http://amphibiaweb.org/ AmphibiaWeb]. * [http://www.naturalsciences.org/education/treks/amphibian/2007/pages/Salamander%20Egg%20with%20Algae.html Image of salamander egg with algae] at [http://www.naturalsciences.org/ North Carolina Museum of Natural Sciences].

{{Taxonbar|from=Q7095386|from2=Q27663719}}

Category:Symbiosis Category:Flora of Northern America Category:Chlorococcaceae Category:Plants described in 1909 Category:Chlorophyta species

{{Chlorophyceae-stub}}